Window Frame to Pet Gate: The Hinge Set That Holds
An old window frame becomes a swinging pet gate, but the hinge mortise depth is the difference between a gate that swings true and one that droops within a month.
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That salvaged window frame in your garage has good bones for a pet gate, but most people mount the hinges flush against the surface and wonder why the gate starts sagging within weeks. The real fix is chiseling a shallow mortise so the hinge barrel sits recessed into the wood instead of just screwed onto the surface — that recess is what transfers the gate's weight into the frame itself instead of onto the screw threads alone, which is exactly what keeps it swinging level instead of dragging on the floor after a few months of a dog nosing through it.
What You'll Need
- Old wooden window frame, thrifted or salvaged, single sash, about $10
- Two butt hinges, 3-inch, roughly $6 for the pair
- Wood chisel, for cutting hinge mortises, likely already on hand
- Gate latch or hook-and-eye, about $3
- Wood screws, 3/4-inch, a small box for around $2
- Sandpaper, 120 and 220 grit, a dollar or two
- Paint or clear sealant, optional, around $8
How to Build It
- Measure your doorway opening and confirm the window frame will fit with an inch of clearance on each side for swing space.
- Remove any remaining glass panes carefully and knock out loose glazing putty, wearing gloves the whole time.
- Sand the frame down to bare wood, rounding any sharp edges a curious pet nose might bump into.
- Mark hinge placement on the frame's edge, one hinge 6 inches from the top and one 6 inches from the bottom.
- Chisel a shallow mortise at each mark deep enough that the hinge barrel sits flush with the wood surface rather than proud of it.
- Screw the hinges into the mortises, then attach the opposite hinge leaf to your doorway's frame or a mounted support post.
- Attach the latch at a height your pet can't nose open, testing the swing before final tightening.
- Finish with paint or sealant once you've confirmed the gate swings smoothly and closes flush.
If the frame still has its original glazing bars, leave one small pane of frosted glass or chicken wire in place instead of pulling it all out — it lets light through while still blocking a determined dog, and it reads as an intentional design choice instead of a leftover renovation part.
